"A credible, effective nuclear deterrent is essential to our national security and the security of U.S. allies. Deterrence remains a cornerstone of national security policy in the 21st century. The Navy's TridentII (D5) strategic weapon system provides the most survivable leg of the strategic deterrent Triad," Daniels said.

The Navy said it conducts flight tests on a frequent basis.

"Test flights were not conducted in response to any ongoing world events or as a demonstration of power," Daniels said.

Tuesday's missiles were launched from an Ohio Class SSBN submarine. All missile test flights are launched from sea, flown over the sea,and land in the sea, Daniels said.